Rope

ABSTRACT

The instant invention is a rope. This rope includes a blend of filaments including a first filament, and a second filament. The second filament is fluorocarbon polymer filament.

FIELD OF INVENTION

The instant application relates to a rope for various types ofapplications including, but not limited to, heavy lifting or mooringapplications, such as marine, oceanographic, offshore oil and gas,seismic, and industrial applications.

BACKGROUND OF THE INVENTION

The use of ropes in various applications is widely known. Generally, arope may be a stout cord made of strands of natural or artificial fiberstwisted or braided together, or in the alternative, a rope may be a cordhaving a wire core with fiber strands braided around it.

Different factors must be considered in order to prevent rope failure.These factors include, but are not limited to, rope constructionmethods, fiber selections, and service conditions. Rope failure may becaused by different damage mechanism, e.g. frictional heat generatedwithin the rope, or self-abrasion. The frictional heat generated withina rope may be caused by the bending mechanism; or in the alternative, itmay be cause by the rope rubbing against a drum, a pulley, or a sheave.The frictional heat generated within a rope can be great enough to causea catastrophic failure of the rope. This problem is particularly evidentwhen the fiber material looses a substantial amount of strength, i.e.becoming susceptible to creep rupture, when heated above ambienttemperature.

Different techniques have been employed to improve rope strength. Forexample, jacketing the subropes(or strands) is employed to reduceself-abrasion since it is widely known that the primary occurrence ofself-abrasion is at the intersection between the subropes. Jacketingrefers to the placement of a sleeve material (e.g., woven or braidedfabric) over the subrope, so that the jacket is sacrificed to save thesubrope. These jackets, however, add to the overall diameter, weight,and cost of the rope without any appreciable increase in the rope'sstrength. The larger size is obviously undesirable because it wouldrequire larger drums, pulleys, or sheaves to handle the jacketed rope.In addition, rope jackets make visual inspection of the rope core fibersproblematic because the jacket hides the core fibers. Therefore, whilethis solution may be viable, it is considered unsatisfactory.

U.S. Pat. No. 5,931,076 discloses a method for construction of a largediameter braided rope. The rope is formed of high strength, lowelongation synthetic fibers that are twisted together at a twist factorin the range from about 125 to about 145 to form a plurality ofcomparatively small diameter yarns. The small diameter twisted yarns arethen braided together at a pick multiplier in the range from about 1.0to about 2.0 so as to form a plurality of braided strands, and thestrands, in turn, are braided together with a pick multiplier of about2.0 to about 3.6 so as to form the large diameter braided rope.

U.S. Pat. No. 5,901,632 discloses a method for forming a braided rope.Twisted yarns are first braided together to form braided strands, andthe braided strands are then braided together to form a rope.

U.S. Pat. No. 4,534,163 discloses a synthetic rope or cable. In makingthe synthetic fiber rope or cable, a plurality of filaments are broughtin parallel into a core and compacted by a plurality of ribbons or tapeswound about the core under tension in opposite directions to form auniform jacket that is torsionally stable. An outer sheath which may beurethane or other plastic material is applied to the jacket undersufficient pressure to penetrate the jacket but not the core, and thenthe urethane is cured. This rope or cable has a core of substantiallyparallel filaments free to move within the jacket of ribbons wound aboutthe core and penetrated with urethane or other plastic material.

U.S. Patent Application publication No. US 2004/0069132 discloses alarge diameter rope having improved fatigue life on a sheave, pulley, ordrum. The rope includes a blend of HMPE filaments and liquid crystalpolymer filaments selected from the group of lyotropic polymer filamentsand thermoplastic polymer filaments. The rope may be constructed as abraided rope, a wire-lay rope, or a parallel core rope.

Despite the extensive levels of activity and research efforts indeveloping ropes with high strength for different applications, there isa still a need for a new rope with high strength, low risk of failure,and free of jackets on the subropes or completed ropes. Additionally,the new rope should be suitable for a wide range of applications.

SUMMARY OF THE INVENTION

The instant invention is a rope. This rope includes a blend of filamentsincluding a first filament, and a second filament. The second filamentis a fluorocarbon polymer filament.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there is shown in thedrawings a form that is presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIG. 1A is an elevational view of a length of a first embodiment of arope made according to the present invention;

FIG. 1B is an elevational view of a length of a twisted yarn of the ropeof FIG. 1A;

FIG. 1C is an elevational view of a length of a braided strand of therope of FIG. 1A;

FIG. 1D is an exploded view of an end portion of the first embodiment ofthe rope of FIG. 1A, schematically illustrating the manner in whichtwisted yarns are braided together to form braided strands which arethen braided together to form the rope of FIG. 1A;

FIG. 2A is an elevational view of a length of a second embodiment of arope made according to the present invention;

FIG. 2B is an elevational view of a length of a twisted strand of therope of FIG. 2A;

FIG. 2C is an elevational view of a length of a twisted yarn of the ropeof FIG. 2A;

FIG. 2D is an exploded view of an end portion of a second embodiment ofa rope made according to the present invention, schematicallyillustrating the manner in which twisted yarns are twisted together toform twisted strands which are then twisted together to form a rope;

FIG. 3A is an elevational view of a length of a third embodiment of arope made according to the present invention, schematically illustratingthe manner in which the rope is made; and

FIG. 3B is a cross sectional view of the rope of FIG. 3A along the lines3 b-3 b.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings wherein like numerals indicate like elements,there is shown, in FIGS. 1A -1D, a first exemplary embodiment of a rope10 according to the instant invention. This rope 10 includes a blend offilaments 12. Blend of filaments 12 includes a first filament 14, and asecond filament 16. Blend of filaments 12 may further include a thirdfilament (not shown).

First filament 14 may be any high strength filament. For example, firstfilaments 14 may be high modulus polyethylene filaments (“HMPE”) thatare spun from ultrahigh molecular weight polyethylene (“UHMWPE”) resin.HMPE filaments are commercially available under the tradename ofSPECTRA® from Honeywell Performance Fibers of Colonial Heights, Va., andDYNEEMA® from DSM NV of Heerlen, The Netherlands, and Toyobo CompanyLtd. of Osaka, Japan. In the alternative, the first filament 14 may be aliquid crystal polymer (LCP) filament selected from the group consistingof lyotropic polymer filament and thermotropic polymer filament.Lyotropic polymers decompose before melting but form liquid crystals insolution under appropriate conditions (these polymers are solutionspun). Lyotropic polymer filaments include, for example, aramid andpolyphenylene benzobisoxazole (PBO) fibers. Aramid filaments arecommercially available under the tradename KEVLAR® from Dupont ofWilmington, Del., TECHNORA® from Teijin Ltd. of Osaka, Japan, andTWARONO from Teijin Twaron BV of Arnhem, The Netherlands. PBO fibers arecommercially available under the tradename ZYLON® from Toyobo CompanyLtd. of Osaka, Japan. Thermotropic polymers exhibit liquid crystalformation in melt form. Thermotropic filaments are commerciallyavailable under the tradename VECTRAN® from Celanese Advanced Materials,Inc. of Charlotte, N.C. The first filaments 14 may constitute betweenabout 1 to 99 percent volume of the blend 12.

The second filament 16 may be any filament. For example, second filament16 may be a fluorocarbon polymer. An example of fluorocarbon polymerincludes, but is not limited to, poly(tetrafluoroethylene) (“PTFE”).PTFE fibers filaments are commercially available from W. L. Gore &Associates, Inc. of Newark, Del. and Elkton, Md. The second filaments 16may constitute between about 1 to 40 percent volume of the blend 12.

The third filament (not shown) may be any high strength filament. Forexample, third filaments may be high modulus polyethylene filaments(“HMPE”) that are spun from ultrahigh molecular weight polyethylene(“UHMWPE”) resin. HMPE filaments are commercially available under thetradename of SPECTRA® from Honeywell Performance Fibers of ColonialHeights, Va., and DYNEEMA® from DSM NV of Heerlen, The Netherlands, andToyobo Company Ltd. of Osaka, Japan. In the alternative, the thirdfilament (not shown) may be a liquid crystal polymer (LCP) filamentselected from the group consisting of lyotropic polymer filament andthermotropic polymer filament. Lyotropic polymers decompose beforemelting but form liquid crystals in solution under appropriateconditions (these polymers are solution spun). Lyotropic polymerfilaments include, for example, aramid and polyphenylene benzobisoxazole(PBO) fibers. Aramid filaments are commercially available under thetradename KEVLAR® from Dupont of Wilmington, Del., TECHNORA® from TeijinLtd. of Osaka, Japan, and TWARON® from Teijin Twaron BV of Arnhem, TheNetherlands. PBO fibers are commercially available under the tradenameZYLON® from Toyobo Company Ltd. of Osaka, Japan. Thermotropic polymersexhibit liquid crystal formation in melt form. Thermotropic filamentsare commercially available under the tradename VECTRAN® from CelaneseAdvanced Materials, Inc. of Charlotte, N.C. The third filaments mayconstitute between about 1 to 99 percent volume of the blend 12.

Rope 10 may further include a coating. It is believed, but the inventionshould not be so limited, that the coating improves upon the abrasionresistance of the blend 12. The coating may be any coating. The coatingmay, for example, be a synthetic polymer based product. For example, thecoating may be a polyurethane coating. Rope 10 may have any amount ofcoating. Coating may be applied to rope 10 via known conventionalmethods, which includes but is not limited to, impregnating rope 10 withcoating by soaking rope 10 in the coating.

Rope 10 may have different rope constructions. For example, rope 10 mayhave a rope construction selected from the group consisting of a braidedrope construction, wire-lay rope construction, and parallel core ropeconstruction.

In the manufacture of the rope 10, well-known techniques for makingropes are used. Such methods are further disclosed in U.S. Pat. Nos.4,534,163, 5,931,076, and 5,901,632 incorporated herein by reference.

In construction of the first embodiment of rope 10, referring to FIG.1A-1D, the blend of filaments 12, which includes the first, and secondfilaments 14, and 16, respectively, is twisted together in aconventional manner to form a twisted yarn 20. The number of the first,and second filaments, 14, and 16 twisted together to form the twistedyarn 20 is not limited. Referring to FIG. 1 c, a plurality of twistedyarns 20 is, then in turn, braided together in a conventional manner tofrom a braided strand 22. The number of twisted yarns 20 braidedtogether to form the strand 22 is not limited. A plurality of braidedstrands is, subsequently, braided together in a conventional manner toform the rope 10. The number of braided strands 22 to form the rope 10is not limited.

In an alternative construction of the first embodiment of rope 10, theblend of filaments 12, which includes first filament 14, second filament16, and third filament (not shown) is twisted together in a conventionalmanner to form a twisted yarn 20. The number of the first filament 14,second filament 16, and third filament twisted together to form thetwisted yarn 20 is not limited. Referring to FIG. 1 c, a plurality oftwisted yarns 20 is, then in turn, braided together in a conventionalmanner to from a braided strand 22. The number of twisted yarns 20braided together to form the strand 22 is not limited. A plurality ofbraided strands is, subsequently, braided together in a conventionalmanner to form the rope 10. The number of braided strands 22 to form therope 10 is not limited.

In construction of the second embodiment of rope 10, referring to FIG.2A-2D, the blend of filaments 12, which includes the first, and secondfilaments 14, and 16, respectively, is twisted together in aconventional manner to form a twisted yarn 20 a. The number of thefirst, and second filaments, 14, and 16 twisted together to form thetwisted yarn 20 is not limited. A plurality of the twisted yarns 20 ais, then in turn, twisted together in a conventional manner to from atwisted strand 22 a. The number of twisted yarns 20 twisted together toform the strand 22 a is not limited. A plurality of twisted strands 22 ais, subsequently, twisted together in a conventional manner to form therope 10 a. The number of twisted strands 22 a to form the rope 10 a isnot limited.

In an alternative construction of the second embodiment of rope 10, theblend of filaments 12, which includes the first filament 14, secondfilament 16, and third filament (not shown) is twisted together in aconventional manner to form a twisted yarn 20 a. The number of the firstfilament 14, second filament 16, and third filament twisted together toform the twisted yarn 20 is not limited. A plurality of the twistedyarns 20 a is, then in turn, twisted together in a conventional mannerto from a twisted strand 22 a. The number of twisted yarns 20 twistedtogether to form the strand 22 a is not limited. A plurality of twistedstrands 22 a is, subsequently, twisted together in a conventional mannerto form the rope 10 a. The number of twisted strands 22 a to form therope 10 a is not limited.

In construction of the third embodiment of rope 10, referring to FIG.3A-3B, the blend of filaments 12, which includes the first, and secondfilaments 14, and 16, respectively, is aligned in a substantiallyparallel relation to each other, and then compacted under tension toform a core 24. The number of the first, and second filaments, 14, and16 aligned and compacted together to form the core 24 is not limited.The Core 24 is, subsequently, covered by a covering 26. The covering 26may include, but is not limited to, a synthetic polymer based product.

In an alternative construction of the third embodiment of rope 10, theblend of filaments 12, which includes the first filament 14, secondfilament 16, and third filament (not shown) is aligned in asubstantially parallel relation to each other, and then compacted undertension to form a core 24. The number of the first filament 14, secondfilament 16, and third filament aligned and compacted together to formthe core 24 is not limited. The Core 24 is, subsequently, covered by acovering 26. The covering 26 may include, but is not limited to, asynthetic polymer based product.

Rope sample numbers 1-12 were prepared, and evaluated for theirbend-over-sheave cycle fatigue (fatigue life). Rope sample 1-12 had thefollowing compositions as shown in Table I. The testing conditions areshown in Table II, and the fatigue life of rope samples 1-12 is shown inTable III. TABLE I Composition Rope Rope Of Sample No. Diameter Rope 1 9 mm 100% Technora T200W 2  9 mm 100% Technora T200W, PolyurethaneCoated 3  9 mm  80% Technora T200W/20% poly(tetrafluoroethylene)(“PTFE”) composite 4  9 mm  80% Technora T200W/20%poly(tetrafluoroethylene) (“PTFE”) Composite, Polyurethane Coated 5  9mm 100% Vectran T117 - Waxed, Polyurethane Coated 6  9 mm  80% VectranT117/20% PTFE Composite - Waxed, Polyurethane Coated 7 18 mm  50%Ultrahigh Molecular Weight Polyethylene (“UHMWPE”)/ 50% Vectran T97Composite 8 18 mm  50% UHMWPE/50% Vectran T97 Composite, PolyurethaneCoated 9 18 mm  45% UHMWPE/45% Vectran T97/10% PTFE Composite 10 18 mm 45% UHMWPE/45% Vectran T97/10% PTFE Composite, Polyurethane Coated 1140 mm  50% UHMWPE/50% Vectran T97 Composite, Polyurethane Coated 12 40mm  45% UHMWPE/45% Vectran T97/10% PTFE Composite, Polyurethane Coated

TABLE II Rope Sample Cycling No. Tension Sheave Tension Nominal StrokeFrequency 1-6 7.2 Inch 3,560 Pounds 24 Inches 600 Cycles Per HourAluminum Sheave  7-10   9 Inch Steel 7,500 Pounds 30 Inches 360 CyclesPer Hour Sheave 11-12  46 Inch Steel 60,000 Pounds  120 Inches  360Cycles Per Hour Sheave

TABLE III Rope Sample No. Bend-Over-Sheave Cycle Fatigue 1 15,951 Cycles2 18,255 Cycles 3 25,661 Cycles 4 13,214 Cycles 5  3,650 Cycles 6 20,148Cycles 7 26,852 Cycles 8 12,809 Cycles 9 96,844 Cycles 10 36,486 Cycles11  8,596 Cycles 12 18,450 Cycles

The present invention may be embodied in other forms without departingfrom the spirit and the essential attributes thereof, and, accordingly,reference should be made to the appended claims, rather than to theforegoing specification, as indicated the scope of the invention.

1. A rope comprising: a blend of filaments comprising; a first filament, and a second filament, said second filament being a fluorocarbon polymer filament.
 2. The rope according to claim 1, where in said first filament being a high molecular weight polyethylene filament.
 3. The rope according to claim 2, wherein said rope further comprising a coating.
 4. The rope according to claim 3, wherein said coating being polyurethane.
 5. The rope according to claim 2, wherein said blend of filament further comprising a third filament, said third filament being a high strength filament selected from the group consisting of lyotropic polymer filaments and thermotropic polymer filaments.
 6. The rope according to claim 1, where in said first filament being a high strength filament selected from the group consisting of lyotropic polymer filaments and thermotropic polymer filaments.
 7. The rope according to claim 6, wherein said blend of filament further comprising a third filament, said third filament being a high molecular weight polyethylene filament.
 8. The rope according to claims 1, wherein said rope having a rope construction selected from the group consisting of a braided rope construction, wire-lay rope construction, and parallel core rope construction.
 9. The rope according to claims 1, wherein said fluorocarbon polymer filament being a poly(tetrafluoroethylene) filament.
 10. The rope according to claim 1, wherein said first, and second filaments being twisted together to form a plurality of twisted yarns, said plurality of twisted yarns being braided together to form a plurality of braided strands, and said plurality of strands being braided together to form said rope.
 11. The rope according to claim 1, wherein said first, and second filaments being twisted together to form a plurality of twisted yarns, said plurality of twisted yarns being twisted together to form a plurality of twisted strands, and said plurality of strands being twisted together to form said rope.
 12. The rope according to claim 1, wherein said first, and second filaments forming a core, and said core being covered by a cover.
 13. A method for improving fatigue life of a rope on a sheave, a pulley, or a drum comprising the steps of: providing a first filament; providing a second filament, said second filament being poly(tetrafluoroethylene) filament; twisting said first, and second filaments together thereby forming a plurality of twisted yarns; braiding said plurality of twisted yarns together thereby forming a plurality of braided strands; braiding said plurality of twisted strands together thereby forming a rope having an improved fatigue life on a sheave, a pulley, or a drum.
 14. The method according to claim 13, wherein said first filament being a high molecular weight polyethylene filament.
 15. The method according to claim 14, wherein said method further including the step of providing a third filament subsequent to the step of providing a second filament, and twisting said first, second, and third filaments together thereby forming a plurality of twisted yarns.
 16. The method according to claim 15, wherein said third filament being a high strength filament selected from the group consisting of lyotropic polymer filaments and thermotropic polymer filaments.
 17. The method according to claim 13, wherein said first filament being a high strength filament selected from the group consisting of lyotropic polymer filaments and thermotropic polymer filaments.
 18. The method according to claim 17, wherein said method further including the step of providing a third filament subsequent to the step of providing a second filament, and twisting said first, second, and third filaments together thereby forming a plurality of twisted yarns.
 19. The method according to claim 18, wherein said third filament being a high molecular weight polyethylene filament.
 20. A method for improving fatigue life of a rope on a sheave, a pulley, or a drum comprising the steps of: providing a first filament; providing a second filament, said second filament being a poly(tetrafluoroethylene) filament; twisting said first, and second filaments together thereby forming a plurality of twisted yarns; twisting said plurality of twisted yarns together thereby forming a plurality of twisted strands; twisting said plurality of twisted strands together thereby forming a rope having an improved fatigue life on a sheave, a pulley, or a drum.
 21. The method according to claim 20, wherein said first filament being a high molecular weight polyethylene filament.
 22. The method according to claim 21, wherein said method further including the step of providing a third filament subsequent to the step of providing a second filament, and twisting said first, second, and third filaments together thereby forming a plurality of twisted yarns.
 23. The method according to claim 22, wherein said third filament being a high strength filament selected from the group consisting of lyotropic polymer filaments and thermotropic polymer filaments.
 24. The method according to claim 20, wherein said first filament being a high strength filament selected from the group consisting of lyotropic polymer filaments and thermotropic polymer filaments.
 25. The method according to claim 24, wherein said method further including the step of providing a third filament subsequent to the step of providing a second filament, and twisting said first, second, and third filaments together thereby forming a plurality of twisted yarns.
 26. The method according to claim 25, wherein said third filament being a high molecular weight polyethylene filament.
 27. A method for improving fatigue life of a rope on a sheave, a pulley, or a drum comprising the steps of: providing a first filament; providing a second filament, said second filament being a poly(tetrafluoroethylene) filament; aligning said first, and second filaments in a substantially parallel relation to each other; compacting said aligned first, and second filaments under tension; thereby forming a core; providing a cover; covering said core with said cover; thereby forming said rope.
 28. The method according to claim 27, wherein said first filament being a high molecular weight polyethylene filament.
 29. The method according to claim 28, wherein said method further including the step of providing a third filament subsequent to the step of providing a second filament, aligning said first, second, and third filaments in a substantially parallel relation to each other, and compacting said aligned first, second, and third filaments under tension.
 30. The method according to claim 29, wherein said third filament being a high strength filament selected from the group consisting of lyotropic polymer filaments and thermotropic polymer filaments.
 31. The method according to claim 27, wherein said first filament being a high strength filament selected from the group consisting of lyotropic polymer filaments and thermotropic polymer filaments.
 32. The method according to claim 31, wherein said method further including the step of providing a third filament subsequent to the step of providing a second filament, aligning said first, second, and third filaments in a substantially parallel relation to each other, and compacting said aligned first, second, and third filaments under tension.
 33. The method according to claim 32, wherein said third filament being a high molecular weight polyethylene filament. 